Freedom251 › Mail Server Software
Courier Mail Server

Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Courier Mail Server | Source code distributed under the GNU General Public License | Free |
As courier-mta.org lists them, read 5 Oct 2026. The maker's own page has the final word.
Facts from Courier Mail Server's own pages
- Authentication
- Authentication options include PAM, LDAP, MySQL, and PostgreSQL, with PostgreSQL identified as beta on the features page. · courier-mta.org, 5 Oct 2026
- Calendaring
- Its webmail module includes basic web-based calendaring and scheduling, including a personal event calendar. · courier-mta.org, 5 Oct 2026
- Compatibility
- Courier can be installed on systems previously running sendmail or Qmail, but the site says it is not a fully compatible replacement for either. · courier-mta.org, 5 Oct 2026
- Deployment
- It can act as an intermediate mail relay, receive mail for multiple domains, or do both. · courier-mta.org, 5 Oct 2026
- Distribution
- The download page offers the complete server source tarball and separate packages for components including IMAP, SqWebMail, and maildrop. · courier-mta.org, 5 Oct 2026
- Download
- The download page lists Courier 2.0.7, dated 02-Aug-2026, as a source code tarball containing the mail server, IMAP server, webmail server, and maildrop filter. · courier-mta.org, 4 Oct 2026
- Filtering
- Integrated mail filtering supports administrator-installed external filters and recipient-specified rules through maildrop. · courier-mta.org, 5 Oct 2026
- Integrations
- The server can use LDAP, MySQL, or PostgreSQL-based authentication databases and supports LDAP-based mail routing. · courier-mta.org, 5 Oct 2026
- Limitations
- Courier does not implement ETRN and is not a fully compatible replacement for sendmail or Qmail; its integrated mailbox servers do not support mbox. · courier-mta.org, 4 Oct 2026
- Limits
- Courier does not implement ETRN, and its integrated mailbox access components do not support mbox mailboxes. · courier-mta.org, 5 Oct 2026
- Mailing lists
- Courier includes a mailing list manager with automatic bounce processing. · courier-mta.org, 4 Oct 2026
- Mail services
- Courier is an integrated mail and groupware server providing ESMTP, IMAP, POP3, webmail, and mailing list services. · courier-mta.org, 5 Oct 2026
- Mail storage
- Maildir is its native mail storage format, and integrated IMAP, POP3, and webmail components support maildir-based mailboxes only. · courier-mta.org, 5 Oct 2026
- Platforms
- The source should compile on most Linux and BSD-based POSIX operating systems, and may compile on Solaris and AIX with additional tools. · courier-mta.org, 5 Oct 2026
- Product
- Courier is an integrated mail and groupware server providing ESMTP, IMAP, POP3, webmail, and mailing list services. · courier-mta.org, 4 Oct 2026
- Relay protection
- The site says Courier is a closed mail relay by default and cannot accidentally be configured as a completely open relay. · courier-mta.org, 5 Oct 2026
- Security
- Courier supports STARTTLS and SSL for ESMTP, IMAP, POP3, and webmail; its ESMTP client can require a certificate signed by a trusted root CA. · courier-mta.org, 5 Oct 2026
- Standalone components
- The IMAP server, SqWebMail webmail CGI, and maildrop filter are also offered as separate packages usable with other mail servers. · courier-mta.org, 4 Oct 2026
- Storage
- Maildir is its native storage format; the integrated POP3, IMAP, and webmail servers work with maildir mailboxes only. · courier-mta.org, 4 Oct 2026
- Support
- The site lists an unmoderated courier-users mailing list for questions, bug reports, and comments, plus a separate read-only announcement list. · courier-mta.org, 4 Oct 2026
- Transport security
- The site lists STARTTLS and SSL support for ESMTP, IMAP, POP3, and webmail, and says the ESMTP client can require trusted-root-signed X.509 certificates. · courier-mta.org, 4 Oct 2026
- Web administration
- Most configuration can be adjusted through a web-based administration module. · courier-mta.org, 5 Oct 2026
Where Courier Mail Server stands on Freedom251
- Mail Server Software#8 of 34